The Prime95 argument is flawed.
If you're using a system for games and it doesn't crash any game with a beefy overclock I'd call that stable.
If you're using a system for heavy photoshop or 3D work and it doesn't crash whilst rendering then I'd call that a stable overclock.
I expect my car would sit on cruise control for a while at 110mph but no doubt struggle to maintain it. Do I drive everywhere at 110mph? No.
Whatever test method you use, it has to match your everyday usage or you'll never truly know if you've hit the sweet spot.
Instability doesn't always result in hard crashes though, that's just the most obvious outcome. A few mathematical errors can just cause weird glitches in games such as in the physics or corrupting saves, or in the case of Photoshop/CAD anomalies in the project being rendered.
At the end of the day it comes down to your definition of 'stability', for some people it just means an application not completely crashing whereas for others and 100% of serious industry it means computational/data integrity (ie. 2+2=4 instead of 2+2=5).
I don't know what all the fuss is about TBH...
Here is my E6400 a 2.13ghz chip running @ 4.119 ghz under my Phase change unit Idle temps -19c load temps 7c
All Ive asked is that anyone can post a Ryzen 1700 running Prime small FFT @4ghz
I test all my clocks using various methods....But my starting point has always been prime....
Over the years I have overclocked chips to their max and then I dial back so I can use my PC in confidence...It can add up, game, render video anything...
My PC is a tool and I want it function correctly...I want it to do its job...I don't want crashes and BSOD when using it....So I test it for stability...
I've done it with my P3,P4 AMD opteron 170, Countless conroe Chips...Q6600 quad cores....i5,i7 and 5820K, 6700K and I will be doing it with Ryzen...
CPU clocking is no different that of GPU clocking....Thats why we run Firestrike..3D mark, Heaven...We clock the GPU and PASS these tests....Now I use this foundation for my clocking....
I could be running in Game in Borderlnads 2 with a clocked GPU and it wouldn't crash...Run the same clocks in Heaven....And I could get Hangs...
The GPU might play in another game, but the crash in others...This is why we test first in Benchies that stress the GPU...Usually a sucessful run in a benchmark would transfer to stability in gaming...
Usually a successful Prime run alongside other test would lead to a stable system for numerous scenarios...
The good old days....
Maxed out the mobo, not the chip
1.7v in bios to see how the phase copes for when i get a 9x multi chip
Setter with his 8 hour Prime run with Q6600
12 hours Prime with My Opteron 170
This Prime buisness has been used for years and years...